Pros
If you're in the right team, working at Cummins is the best decision you'll ever make. The cross-functional nature of the company allows an employee to grow everyday and move between various functions if he/she chooses to do so. Management is usually supportive and provides the tools/experience that the employee needs. And amongst its peers, the company is doing exceedingly well which translates into a great working environment.
Cons
I'm aware of teams around the company that do not have a very open environment, teams that are confrontational when asked for information/assistance and managers that do not care about their direct reports. There are also teams that unnecessarily force Six Sigma down employees' throats when the concept should really be used to implement true change/improvement.